Investigating the specificity of neuropsychological performance in bulimic outpatients : a comparison with anxious and depressed outpatients
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Eating Disorder research has highlighted the role of neuropsychological functioning, informing the treatment of Anorexia Nervosa. There is ambiguity in the data relating to cognitive impairment in Bulimia Nervosa, with the latest review providing inconclusive results. Executive function impairments in the area of set shifting and inhibition reported in BN are proposed to relate to traits of compulsivity and impulsivity. Other psychological disorders have also demonstrated executive function impairments. Among anxiety disorders, only PTSD and OCD have strong evidence of executive function deficits while a number of studies point towards executive function deficits in depression. This thesis aims to investigate the specificity of cognitive impairments seen in a group of female outpatients with bulimia nervosa, using a clinical comparison group of anxious and/or depressed female outpatients. Methods A systematic review was conducted to address a gap in the anxiety disorder literature and assess the neuropsychological profile of panic disorder. In order to address the main study aims, a comparison between a group of patients with BN and an anxious depressed group was conducted on neuropsychological measures of the Trail Making Test, Wisconsin Card Sorting Test, Hayling and Brixton tasks, Stroop and Verbal Fluency. In addition, psychological symptoms were assessed using SCL-90-R, Yale- Brown Obsessive Compulsive Scale and the Self-liking Self Competence scale. Social problems solving skills were assessed as a potential real world effect of executive function difficulties associated with eating disorders. The relationships between psychological and neuropsychological variables were investigated. Results The systematic review concluded that there was limited evidence of specific impairment in short term memory in panic disorder. The empirical study indicated no group differences on the above neuropsychological measures. Groups also did not differ on NART estimated IQ or self reported psychological symptoms. No relationships were found between psychological symptoms and neuropsychological measures. Few individual participants were found to be impaired on neuropsychological measures in either group. However, those impaired in the BN group were exclusively impaired on the non-perseverative errors and categories completed variables of the WCST, which is thought to be related to impulsivity. Conclusion These findings suggest that the neuropsychological profile of bulimia is broadly similar to that of an anxious and/or depressed clinical group on measures of set shifting and inhibition. Although there was evidence of a deficit in inhibition among patients with bulimia further investigation is required.